Patent Document 1 (identified below) discloses an LC filter. The LC filter of Patent Document 1 includes a multilayer body, coil conductor patterns, and a chip capacitor component.
The multilayer body is formed by stacking and heat-pressing a plurality of thermoplastic resin sheets. The conductor patterns are formed on a predetermined plurality of the thermoplastic resin sheets. The coil conductor patterns of the plurality of thermoplastic resin sheets are connected by interlayer connection conductors. As a result, a helical coil is formed in the multilayer body. A chip capacitor is disposed in the multilayer body so as to overlap the central cavity of the helical coil.
Patent Document 1: International Publication No. JPWO2015/194373 patent.
However, in the LC filter having the structure described in Patent Document 1, because the thermoplastic resin sheets flow during heat-pressing, the shape of the coil conductor patterns may collapse in some cases. If the shape of the coil conductor patterns collapses, filter characteristics desirable for a coil may not be achieved in some cases. In particular, in helical coils, variations in coupling capacitances between coil conductor patterns aligned in the stacking direction become large, and it is difficult to stably obtain desired filter characteristics (S11, S21, and the like).
In addition, in the configuration described in Patent Document 1, because the chip capacitor is incorporated in the multilayer body and a hole for accommodating the chip capacitor is not provided in the multilayer body, the flatness of the front surface and the rear surface of the multilayer body ends up being reduced. When the flatness of the front surface and the rear surface of the multilayer body is reduced, mounting defects are likely to occur.